I'm a big fan of the materials the State of Texas has put together at http://gov.texas.gov/disabilities/accessibledocs/
The material is arranged in a series of "bite-sized" modules, so you can do as many as you can absorb, and go back for quick refreshers on specific topics. The modules are available in range of formats: video, MP3 audio, Word, and PDF.

The focus is on creating the original documents properly. The PDF module does not go into very much depth - just the basics!